The present disclosure relates to containers for use in high-pressure presses, and more particularly to a container and gasket for use in a high-pressure press to form ultra-hard materials such as diamond and cubic boron nitride, and also relates to methods of sealing a central pressure cell of a high-pressure press.
Ultra-hard materials such as diamond and cubic boron nitride (CBN) are known for their desirable material properties and are used in cutting tools and rock drilling tools. These ultra-hard materials are formed by a high-pressure high-temperature sintering process (“HPHT sintering”), in which ultra-hard material particles are subjected to high temperature and pressure in a high-pressure press. The HPHT sintering process can include pressing the materials at a pressure not less than the 5 GPa and generally in the range of 5 to 15 GPa at an elevated temperature of not less than 1300° C. and generally in the range of 1300-2400° C.
This HPHT sintering process is conducted with a high-pressure press, such as a cubic press, a belt press, or a toroid press. The ultra-hard material sample that is being pressed is placed inside a container that is placed inside the press. To successfully transmit ultra-high pressures to the material sample inside the container, many requirements are placed on the container. The container should be sufficiently deformable to transmit pressure to the sample being pressed, and it should be able to flow during compression and decompression. However, the container should also have sufficient strength to seal the central pressure cell so that high pressure can be developed within the cell. In a high-pressure, multi-anvil press, the behavior of the container material is dynamic as the material flows from one region to another at different stages of the press cycle. Accordingly, there is still a need for a container that satisfies conflicting demands to transmit pressure and seal the high pressure cell during complex high pressure operations.